不同树龄次生甜槠木荷林的树种组成与空间结构比较研究

为了进一步揭示次生甜槠Castanopsis eyrei木荷Schima superba林的林分空间结构特征,在浙江省遂昌县垵口村的20～25年生、35～40年生、55～60年生3个次生甜槠木荷林分别设置了面积为50 m×50 m的样地,进行了每木调查和坐标定位。通过样地Ripley聚集度分析和点Ripley聚集度分析,对3个样地中的优势树种及林分整体的空间格局进行对比分析。结果表明:随着树龄的增加,不同年龄的次生甜槠木荷林的上层乔木立木数量逐渐增加,下层乔木立木数量逐渐减少,树种数量相对稳定,但各层树种组成变化明显,其中上层木中甜槠、木荷、青冈Cyclobalanopsis glauca 3个优势种的比例从20～25年生时的20.41%增长到55～60年生时的73.53%;从空间结构看,20～25年生甜槠木荷林林分呈现聚集分布,35～40年生甜槠木荷林林分呈现半聚集半均匀分布状态,55～60年生甜槠木荷林林分呈现均匀分布。

Comparisonon Species Composition and Spatial Structure of Different Aged Secondary Forest of Castanopsis eyrei-Schima superba

During October and December of 2017, three sample plots with 50 m × 50 m were set up in 20-25, 35-40 and 55-60-year secondary Castanopsis eyrei-Schima superba forest in Suichang, Zhejiang province. Complete enumeration was made in the sample plot. The results showed that treenumbers of overstory increased and that of understory decreased with increase of forest age. Species number maintained stable while species composition of different storey changed evidently. The proportion of three dominant species of the over story such as C. eyrei, S. superba and Cyclobalanopsis glauca increased from 20.41% at 20-25-year forest to 73.53% at 55-60-year forest. The analysis demonstrated that 20-25-year stand was aggregated distribution, 35-40-yearsemi-aggregated one, and 55-60 year uniform distribution.